Epidemiological study of pestiviruses in South American camelids in Switzerland

BACKGROUND: In the context of the ongoing eradication campaign for bovine viral diarrhea virus (BVDV) in cattle in Switzerland, the role of South American camelids (SAC) as a possible virus reservoir needed to be evaluated. OBJECTIVE: To assess and characterize the prevalence of pestivirus infections in SAC in Switzerland. ANIMALS: Serum samples collected from 348 animals (40 herds) in 2008 and from 248 animals (39 herds) in 2000 were examined for antibodies against pestiviruses and for the presence of BVDV viral RNA. METHODS: Cross-sectional study using stratified, representative herd sampling. An indirect BVDV-ELISA was used to analyze serum samples for pestivirus antibodies, and positive samples underwent a serum neutralization test (SNT). Real-time RT-PCR to detect pestiviral RNA was carried out in all animals from herds with at least 1 seropositive animal. RESULTS: In 2008, the overall prevalence of animals positive for antibodies (ELISA) and pestiviral RNA or was 5.75 and 0%, respectively. In 2000, the corresponding prevalences were 3.63 and 0%, respectively. The seroprevalences (SNT) for BVDV, border disease virus or undetermined pestiviruses were estimated to be 0, 1.73, and 4.02% in 2008, and 0.40, 1.21, and 2.02% in 2000, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: At the present time, SAC appear to represent a negligible risk of re-infection for the BVDV eradication program in cattle in Switzerland.

Immunohistochemical screening for viral agents in cheetahs (Acinonyx jubatus) with myelopathy

Numerous cases of acute-onset progressive ataxia, hindlimb paresis and paralysis of unknown aetiology occurred during 1993 to 2003 in cheetahs (Acinonyx jubatus) within the European Endangered Species Programme (eep). This study describes the immunohistochemical investigation of a possible viral aetiology of the "cheetah myelopathy". Antibodies to feline herpesvirus type 1, canine distemper virus, canine parvovirus and Borna disease virus were applied to formalin-fixed and paraffin-embedded brain and spinal cord sections from 25 affected cheetahs aged between three-and-a-half months and 13 years. Using the avidin-biotin complex technique, none of the antibodies gave positive immunosignals in either the brain or the spinal cord tissue.

Seroprevalence and characterization of pestivirus infections in small ruminants and new world camelids in Switzerland

The seroprevalence of pestivirus infections in small ruminants and new world camelids in Switzerland was determined. In 5'059 sera of sheep from 382 herds, 503 sera of goats from 54 herds and 109 sera of alpacas and lamas from 53 herds, population prevalences of 16.1% (sheep), 25.4% (goats) and 4.6% (new world camelids), respectively, were found. In order to determine the source of infection, the serological reactions were further characterized by cross-neutralization against two pestiviruses representing the genotypes BVDV (Bovine Virus Diarrhea Virus)-1 and BDV (Border Disease Virus)-1. Based on the ratio of respective antibody titres, 56.1% of the infections in sheep were induced by a BDV-1, 12.9% by a BVDV-1 and 31.0% by an unresolved pestivirus. In goats, the corresponding proportions were 23.4%, 10.2% and 66.4%, respectively. In Alpacas and Lamas, the source of infection of 1 animal was BDV-1 and that of 4 seropositive animals remained unresolved. In view of the phylogenetic relationship between pestiviruses, the unresolved source of infection is most probably attributable to other pestivirus genotypes circulating in small ruminants and new world camelids. Due to the predominance of pestiviral genotypes other than BVDV-1, the risk of transmission of BVDV from persistently infected small ruminants and new world camelids to cattle appears to be moderate, apart from close direct contact in mixed animal husbandry, communal pasturing and grazing in the Alps.

Pestiviruses.

Pestiviruses cause economically important diseases among domestic ruminants and pigs, but they may also infect a wide spectrum of wild species of even-toed ungulates (Artiodactyla). Bovine viral diarrhea virus (BVDV) and Border disease virus of sheep infect their hosts either transiently or persistently. Cellular and humoral immunotolerance to the infecting strain is a unique feature of persistent infection (PI) by ruminant pestiviruses. Persistence, caused by transplacental infection early in fetal development, depends on virally encoded interferon antagonists that inactivate the host's innate immune response to the virus without globally interfering with its function against other viruses. At epidemiological equilibrium, approximately 1-2% of animals are PI. Successful BVDV control programs show that removal of PI animals results in viral extinction in the host population. The nucleotide sequences of ruminant pestiviruses change little during persistent infection. Nevertheless, they display large heterogeneity, pointing to a long history of virus-host coevolution in which avirulent strains are more successful.

Viral capsid mobility: A dynamic conduit for inactivation

Mass spectrometry and fluorescent probes have provided direct evidence that alkylating agents permeate the protein capsid of naked viruses and chemically inactivate the nucleic acid. N-acetyl-aziridine and a fluorescent alkylating agent, dansyl sulfonate aziridine, inactivated three different viruses, flock house virus, human rhinovirus-14, and foot and mouth disease virus. Mass spectral studies as well as fluorescent probes showed that alkylation of the genome was the mechanism of inactivation. Because particle integrity was not affected by selective alkylation (as shown by electron microscopy and sucrose gradient experiments), it was reasoned that the dynamic nature of the viral capsid acts as a conduit to the interior of the particle. Potential applications include fluorescent labeling for imaging viral genomes in living cells, the sterilization of blood products, vaccine development, and viral inactivation in vivo.

Local nitric oxide production in viral and autoimmune diseases of the central nervous system.

Because of the short half-life of NO, previous studies implicating NO in central nervous system pathology during infection had to rely on the demonstration of elevated levels of NO synthase mRNA or enzyme expression or NO metabolites such as nitrate and nitrite in the infected brain. To more definitively investigate the potential causative role of NO in lesions of the central nervous system in animals infected with neurotropic viruses or suffering from experimental allergic encephalitis, we have determined directly the levels of NO present in the central nervous system of such animals. Using spin trapping of NO and electron paramagnetic resonance spectroscopy, we confirm here that copious amounts of NO (up to 30-fold more than control) are elaborated in the brains of rats infected with rabies virus or borna disease virus, as well as in the spinal cords of rats that had received myelin basic protein-specific T cells.

Functional memory CD8+ T cells can be generated in vivo without evident T help

Synthetic cytotoxic T cell (CTL) epitope peptides provide an effective and safe means of vaccination against cancers and viruses, as these peptides can induce specific CD8+ effector T cells in vivo. However, the effector CD8+ T cells induced by the minimal CTL epitope peptides do not last past about 3 weeks after the induction and no functional memory CD8+ T cells are generated. It is held that simultaneous induction of CD4+ T cells by incorporating peptides containing T-helper epitopes in the vaccine at the time of primary vaccination are necessary for the induction of long-lived functional memory CD8+ T cells. We now report that, surprisingly, incorporation of medium length (>20 AA) peptides devoid of detectable T-helper epitopes in a minimal CTL epitope-based vaccine can also induce long-lasting! functional rumour antigen specific memory CD8+ T cells that are capable of promoting protection against tumour challenge. This observation may have implications for the formulation of therapeutic anti-cancer and anti-virus peptide vaccines where a strong induction of CD4 T help would be undesirable. (C) 2004 Elsevier Ltd. All rights reserved.

Is the distribution of Fiji leaf gall in Australian sugarcane explained by variation in the vector Perkinsiella saccharicida?

Fiji leaf gall (FLG) is an important virally induced disease in Australian sugarcane. It is confined to southern canegrowing areas, despite its vector, the delphacid planthopper Perkinsiella saccharicida, occurring in all canegrowing areas of Queensland and New South Wales. This disparity between distributions could be a result of successful containment of the disease through quarantine and/or geographical barriers, or because northern Queensland populations of Perkinsiella may be poorer vectors of the disease. These hypotheses were first tested by investigating variation in the ITS2 region of the rDNA fragment among eastern Australian and overseas populations of Perkinsiella. The ITS2 sequences of the Western Australian P. thompsoni and the Fijian P. vitiensis were distinguishable from those of P. saccharicida and there was no significant variation among the 26P. saccharicida populations. Reciprocal crosses of a northern Queensland and a southern Queensland population of P. saccharicida were fertile, so they may well be conspecific. Single vector transmission experiments showed that a population of P. saccharicida from northern Queensland had a higher vector competency than either of two southern Queensland populations. The frequency of virus acquisition in the vector populations was demonstrated to be important in the vector competency of the planthopper. The proportion of infected vectors that transmitted the virus to plants was not significantly different among the populations tested. This study shows that the absence of FLG from northern Queensland is not due to a lack of vector competency of the northern population of P. saccharicida.

Husbandry and trade of indigenous chickens in Myanmar - results of a participatory rural appraisal in the Yangon and the Mandalay divisions

There is a variety of professions working with village chickens in developing countries, including farmers, veterinarians and chicken traders. People from all these occupations were involved in a participatory rural appraisal to investigate husbandry practices and trade of village chickens in Myanmar. Data were collected in two climatically different regions of the country, in the Yangon and in the Mandalay divisions. The breeding and training of fighting cocks was practised only in the Mandalay division, with well-trained birds sold for very high prices. Apart from this, chickens were raised in both regions mainly for small disposable income and were generally sold when money was needed, in particular during religious festivals. Chicken traders on bicycles, often called 'middle men', usually purchase birds from farmers in about 10 villages per day. Several 'middle men' supply birds to wealthier chicken merchants, who sell these birds at larger chicken markets. There is in general limited knowledge among farmers about the prevention of Newcastle disease via vaccination. Commercial indigenous chicken production is practised in Myanmar, but family poultry farming dominates indigenous chicken production in the country.

MOSQUITO CONTROL AND ZIKA

This checklist is a tool to help local governments prepare for mosquito season and potential mosquito-borne disease outbreaks. It contains recommended items to be considered as part of a Zika readiness plan.

Proposal to minimize the difficulty of recording abortion data in sheep

Background: The most frequent viral diseases which can cause abortion in sheep are Blue tongue, Border disease virus, Cache Valley fever and Schmallenberg virus. The diagnosis of abortion, namely virus-induced represents a challenge to field clinicians, since clinical signs presented by the dam are discrete, non-specific and variable (Agerhom et al., 2015). On the other hand, while some foetuses reveal characteristic and visible malformations, others do not reveal any lesions. In face of it, definitive diagnosis requires an appropriate history collection, as well as sending fresh samples, namely abortion material, foetus, placenta and umbilical cord, to a specialty laboratory, to obtain a precise diagnosis. Objectives: The authors suggest a registration method of all mandatory data, in order to further assist the diagnosis of viral diseases at the laboratories, including the most frequent congenital malformations reported in sheep abortions. Methods: Abortion samples of suspected viral origin were collected and all data were registered, in worktables optimized for this purpose. Results: The authors document, using macroscopic figures lesions of malformations in abortions, emphasizing the frequency and the importance of documenting each case, proposing practical and effective worktables to assist the fieldwork. Conclusions: Field clinician’s awareness of the importance of early detection of viral diseases causing abortion outbreaks stimulates a proper data collection for each case of abortion, in order to contribute to a precise diagnosis and posterior consistent epidemiological studies, which may allow diminishing of economic losses.

Estudo de parâmetros clínicos, imunitários e do proteinograma sérico da vacinação contra a doença de Newcastle em gansos-da-China (Anser cygnoides): pesquisa do estado portador do vírus e sua importância epidemiológica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Immunization with DNA vaccines encoding glycoprotein D or glycoprotein B, alone or in combination, induces protective immunity in animal models of herpes simplex virus-2 disease.

DNA vaccines expressing herpes simplex virus type 2 (HSV-2) full-length glycoprotein D (gD), or a truncated form of HSV-2 glycoprotein B (gB) were evaluated for protective efficacy in two experimental models of HSV-2 infection. Intramuscular (i.m.) injection of mice showed that each construction induced neutralizing serum antibodies and protected the mice from lethal HSV-2 infection. Dose-titration studies showed that low doses (< or = 1 microgram) of either DNA construction induced protective immunity, and that a single immunization with the gD construction was effective. The two DNAs were then tested in a low-dosage combination in guinea pigs. Immune sera from DNA-injected animals had antibodies to both gD and gB, and virus neutralizing activity. When challenged by vaginal infection with HSV-2, the DNA-immunized animals were significantly protected from primary genital disease.

In vivo activation of melanoma-specific CD8(+) T cells by endogenous tumor antigen and peptide vaccines. A comparison to virus-specific T cells.

Many new types of vaccines against infectious or malignant diseases are currently being proposed. Careful characterization of the induced immune response is required in assessing their efficiency. While in most studies human tumor antigen-specific T cells are analyzed after in vitro re-stimulation, we investigated these T cells directly ex vivo using fluorescent tetramers. In peripheral blood lymphocytes from untreated melanoma patients with advanced disease, a fraction of tumor antigen (Melan-A/MART-1)-specific T cells were non-naive, thus revealing tumor-driven immune activation. After immunotherapy with synthetic peptides plus adjuvant, we detected tumor antigen-specific T cells that proliferated and differentiated to memory cells in vivo in some melanoma patients. However, these cells did not present the features of effector cells as found in cytomegalovirus specific T cells analyzed in parallel. Thus, peptide plus adjuvant vaccines can lead to activation and expansion of antigen specific CD8(+) T cells in PBL. Differentiation to protective CD8(+) effector cells may, however, require additional vaccine components that stimulate T cells more efficiently, a major challenge for the development of future immunotherapy.

West Nile virus vaccines

West Nile virus (WNV) is a mosquito-borne flavivirus that is emerging as a global pathogen. In the last decade, virulent strains of the virus have been associated with significant outbreaks of human and animal disease in Europe, the Middle East and North America. Efforts to develop human and veterinary vaccines have taken both traditional and novel approaches. A formalin-inactivated whole virus vaccine has been approved for use in horses. DNA vaccines coding for the structural WNV proteins have also been assessed for veterinary use and have been found to be protective in mice, horses and birds. Live attenuated yellow fever WNV chimeric vaccines have also been successful in animals and are currently undergoing human trials. Additional studies have shown that immunisation with a relatively benign Australian variant of WNV, the Kunjin virus, also provides protective immunity against the virulent North American strain. Levels of efficacy and safety, as well as logistical, economic and environmental issues, must all be carefully considered before vaccine candidates are approved and selected for large-scale manufacture and distribution.